The primary technology for detecting hydrocarbons are the pellistor sensors. Usually, these sensors are both reliable and cost-effective. They monitor the flammable levels of combustible gases.

However, there are times where it is advised in which the use of pellistors shouldn’t be used. Where other sensors, such as infrared, should be used.

Pellistor Issues

As with every technology there are limits. Where pellistors are known to be a reliable detector of flammable gases, there are situations where the sensor shouldn’t be assumed to be most suitable.

Possibly one of the biggest drawbacks of the pellistor is that they’re prone to poisoning (irreversible loss of sensitivity) or inhibition (reversible loss of sensitivity) by being in contact or exposure with chemicals within the related industries.

Poisoning of a Pellistor, and What Happens?

When a pellistor is poisoned it will produce no output when exposed to flammable gases. Because of this, the detector will not go into alarm, giving the impression that the environment is safe.

Compounds that contain silicon, lead, sulphur, and phosphates just a few parts per million (ppm) can damage the pellistors effectiveness. something innocent such as cleaning equipment or hand cream could be damaging your sensor. Therefor something in your general working environment could be compromising your sensor’s effectiveness.

What makes silicon’s so bad?

Silicon’s have their advantages; however, they may be more common than you may think; sealants, adhesives, lubricants, and thermal and electrical insulations, are just some of the areas in which silicon can be located. The poisoning of pellistor sensors can come at extremely low levels. For instance, if a company were to replace a window pane in the room where they store their gas detecting instruments, and a standard silicon-based sealant was used. This could result in all of their pellistor sensors to fail their testing.

Situations like this highlight the importance of bump testing your equipment. As it will diagnose if a sensor is poisoned or inhibited.

Things you can do to avoid poisoning a sensor

The most important thing you can do is to bump-test your equipment on a regular basis. While testing is important another thing you can do is make sure your detectors are suited to the environment that you’re working in.

If you need you gas detectors service to make sure they are suited for the environment they are working in, please contact our service team and they will be able to provide you a quote within two business days of receiving the instrument.*

We also supply units for hire, which will ensure that the instrument is working perfectly. Please contact us to order your hire unit today.